Preparation and Characterization of Electric Double-Layer Capacitors Having a 3D Stainless-Steel Fiber Sheet as the Current Collector

Abstract

One strategy to improve the performance of electric double-layer capacitors (EDLCs) is changing the current collector material. In this study, a three-dimensional porous current collector comprising stainless-steel fibers is fabricated using a relatively simple method. Capacitor properties of the EDLC using this unique current collector are characterized by cyclic voltammetry and charge–discharge tests. The voltammograms of the EDLC develop a more butterfly shape and an increased specific capacity at higher electrolyte concentrations. It shows reversible charge–discharge potential profiles, little capacity degradation (∼98% of the initial capacity at 1000th cycle), and a good rate performance at higher electrolyte concentrations (90% capacity retention for 2.5 times increase in discharge current). Its capacitance values (95–99 F g –1 ) are roughly twice the specific capacitance of an EDLC using the flat stainless-steel plate current collector (51 F g –1 ) without any performance degradation even at a higher loading of electrode active materials. Based on the AC impedance analysis, these good properties are attributed to the reduction in several resistances compared to the case of a flat stainless-steel plate: (i) the contact resistance between the electrode active material and the current collector, (ii) the resistance of the electrolyte in the finely branched space formed by the fibers and the active material, and (iii) the resistance in the diffusion layer. Increasing the electrolyte concentration further reduces the latter two resistances and the bulk electrolyte resistance, resulting in higher performance of the EDLC using the stainless-steel fiber sheet current collector.

Tuning Surface Energy to Enhance MoS2 Nanosheet Production via Liquid-Phase Exfoliation: Understanding the Electrochemical Adsorption of Cesium Chloride

“…The adsorbing charge values obtained from various concentrations of the CsCl solution at 0.1 V s –1 are shown in Figure b. The adsorbing charge increases from 0.6 to 1.4 C g –1 (calculated via eq S1), with an increase of concentration from 0.001 to 1 M. This phenomenon is explained by the easier passage of ions through the electrode, which leads to a notable rise in capacitance . Note that the calculation of adsorbing charge values is shown in Figure S3.…”

“…The adsorbing charge increases from 0.6 to 1.4 C g −1 (calculated via eq S1), with an increase of concentration from 0.001 to 1 M. This phenomenon is explained by the easier passage of ions through the electrode, which leads to a notable rise in capacitance. 59 Note that the calculation of adsorbing charge values is shown in Figure S3. On the other hand, it is evident that the onset potential (E onset ) values of the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) from CV curves in Figure 6c are shifted.…”

Ultrafast and Reversible Superwettability Switching of 3D Graphene Foams via Solvent-Exclusive Plasma Treatments

“…Finally, we applied EIS to characterize solution resistance ( R s ) and charge transfer resistance ( R ct ) in our EDLCs (Figures D and S25, and Table S4) as both parameters are used to describe ion mobility in an EDLC. , Polarity matching is expected to decrease R s and R ct due to the shortening of ion diffusion length of multiple ion-transport channels. , Indeed, EDLCs containing superhydrophobic (Figure D, left, red) and superhydrophilic (blue) 3D GFs with nonpolar EMIM-TFSI displayed R s = 3.3 (matched) and 85.3 Ω (mismatched), respectively, resulting in 25.8 times lower solution resistance in the polarity matched case. Furthermore, with polarity matching, an R ct of 19.3 Ω was obtained, 161.3 times lower than with mismatching, indicating significantly faster charge transfer at the electrode–electrolyte interface .…”

Activated of Waste Palm-Oil Based on Chemical-Assisted Microwave Radition for Supercapacitor Materials

“…Therefore, it is theoretically capable of high and fast current charging/discharging and has a long cycle life. The EDLC structure is divided into three parts, namely electrodes, electrolytes, and separators (Muramatsu et al, 2022). Also, the study using machine learning was done for observing properties of biomass as supercapacitor (Jamaluddin et al, 2023).…”